Zimmer is one of seven pitchers on the list, along with fellow righties Jason Adam, Aaron Brooks, Sugar Ray Marimon, Corey Wade and P.J. Walters and left-hander Scott Alexander. Zimmer was the fifth overall pick in the 2012 First-Year Player Draft and is a converted infielder, but he advanced in 2013 all the way to Double-A Northwest Arkansas, where he went 2-1 with a 1.93 ERA in four late-season starts.
Adam, also 22, is the No. 18 Royals prospect on MLB.com's list.
Among the non-roster position players invited to Royals camp are veteran catcher Ramon Hernandez, who agreed to a Minor League contract just this week, and outfielder Jorge Bonifacio, the Royals' No. 5 prospect. Bonifacio batted .298 with a .372 on-base percentage at three affiliates in 2013 and is bidding to join his older brother, Emilio, in the Major Leagues.
The Royals acquired Emilio Bonifacio from the Blue Jays for cash late last season. They signed Jorge out of the Dominican Republic in December 2009.
Other non-roster position players who garnered invitations to manager Ned Yost's big league camp are catchers Juan Graterol and Adam Moore, infielders Jason Donald and Brandon Laird, and outfielders Gorkys Hernandez, Melky Mesa and Paulo Orlando.
Wade, Walters, Hernandez, Moore, Donald, Laird, Hernandez and Mesa all have played in the big leagues.
Kansas City's pitchers and catchers will report to Surprise, Ariz., on Friday, Feb. 14, and workouts for pitchers begin the following day. The remainder of the squad will report on Wednesday, Feb. 19, and the first full-squad workout is Feb. 20.